SFL1/YOR140W Summary Help

Standard Name SFL1 1
Systematic Name YOR140W
Feature Type ORF, Verified
Description Transcriptional repressor and activator; involved in repression of flocculation-related genes, and activation of stress responsive genes; negatively regulated by cAMP-dependent protein kinase A subunit Tpk2p; premature stop codon (C1430T, Q477-stop) in SK1 background is linked to the aggressively invasive phenotype of SK1 relative to BY4741 (S288C) (1, 2, 3, 4, 5, 6 and see Summary Paragraph)
Name Description Suppressor gene for FLocculation 1
Chromosomal Location
ChrXV:586981 to 589281 | ORF Map | GBrowse
Gene Ontology Annotations All SFL1 GO evidence and references
  View Computational GO annotations for SFL1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Targets 6 genes
Regulators 12 genes
Classical genetics
Large-scale survey
168 total interaction(s) for 124 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 7
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 5
  • Biochemical Activity: 1
  • Reconstituted Complex: 1
  • Two-hybrid: 3

Genetic Interactions
  • Dosage Rescue: 1
  • Negative Genetic: 98
  • Phenotypic Enhancement: 3
  • Phenotypic Suppression: 29
  • Positive Genetic: 9
  • Synthetic Growth Defect: 6
  • Synthetic Lethality: 3
  • Synthetic Rescue: 1

Expression Summary
Length (a.a.) 766
Molecular Weight (Da) 83,344
Isoelectric Point (pI) 9.13
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXV:586981 to 589281 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 2011-02-03
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..2301 586981..589281 2011-02-03 2011-02-03
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000005666

Originally identified as a Suppressor gene for FLocculation, SFL1 encodes a 766-amino acid transcriptional repressor of flocculation-related genes (1, 2). SFL1 is required for normal cell-surface assembly in vegetative growth (1), and deletion enhances pseudohyphal and invasive growth (2).

Sfl1p contains two domains homologous to Myc oncoproteins and the yeast heat shock transcription factor Hsf1p (1). The Myc homologous region in Sfl1p overlaps with conserved regions in other eukaryotic proteins including mammalian MyoD1 and immunoglobulin enhancer-binding proteins, as well as Drosophila achaete-scute, twist and daughterless gene products. The N-terminal region of Sfl1p shows homology to the DNA-binding domain of Hsf1p (1).

Two-hybrid analysis has indicated that Sfl1p interacts specifically with Tpk2p, the catalytic subunit of protein kinase A, which negatively regulates Sfl1p function (2, 4, 3). Phosphorylation by protein kinase A relieves Sfl1p-mediated repression by prohibiting dimerization and DNA-binding by Sfl1p (4), and a tpk2Delta mutation increases the levels of Sfl1p protein associated with specific promoter elements (3).

Yeast two-hybrid and GST chromatography interaction experiments determined that Sfl1p interacts directly with Cyc8p, a component of the general corepressor Cyc8p-Tup1p that inhibits the transcription of many diversely regulated genes (3). Electrophoretic mobility shift and chromatin immunoprecipitation assays demonstrate that Sfl1p is present at the promoters of Cyc8p-Tup1p-repressible genes, and repression data suggest that Sfl1p inhibits transcription by recruiting Cyc8p-Tup1p via a specific domain in the Sfl1p protein (3). Co-immunoprecipitation experiments link Sfl1p to Ssn2p, Ssn8p, Sin4p and Rox3p, suggesting that Sfl1p may interact with Srb/mediator proteins to inhibit transcription by the RNA polymerase II holoenzyme (7). Sin4p and Ssn3p, components of specific RNA polymerase II subcomplexes required for Cyc8p-Tup1p repression activity, are required for Sfl1p repression function, indicating a possible mechanism for Sfl1p-mediated repression via Cyc8p-Tup1p and specific subunits of the RNA polymerase II holoenzyme (3). Taken together with previous data, these observations suggest a link between cAMP signaling and Cyc8p-Tup1p-mediated transcriptional repression (3).

Last updated: 2005-05-03 Contact SGD

References cited on this page View Complete Literature Guide for SFL1
1) Fujita A, et al.  (1989) Domains of the SFL1 protein of yeasts are homologous to Myc oncoproteins or yeast heat-shock transcription factor. Gene 85(2):321-8
2) Robertson LS and Fink GR  (1998) The three yeast A kinases have specific signaling functions in pseudohyphal growth. Proc Natl Acad Sci U S A 95(23):13783-7
3) Conlan RS and Tzamarias D  (2001) Sfl1 functions via the co-repressor Ssn6-Tup1 and the cAMP-dependent protein kinase Tpk2. J Mol Biol 309(5):1007-15
4) Pan X and Heitman J  (2002) Protein kinase A operates a molecular switch that governs yeast pseudohyphal differentiation. Mol Cell Biol 22(12):3981-93
5) Ansanay Galeote V, et al.  (2007) Sfl1p acts as an activator of the HSP30 gene in Saccharomyces cerevisiae. Curr Genet 52(2):55-63
6) Song Q, et al.  (2014) Pooled segregant sequencing reveals genetic determinants of yeast pseudohyphal growth. PLoS Genet 10(8):e1004570
7) Song W and Carlson M  (1998) Srb/mediator proteins interact functionally and physically with transcriptional repressor Sfl1. EMBO J 17(19):5757-65
8) Zhu C, et al.  (2009) High-resolution DNA-binding specificity analysis of yeast transcription factors. Genome Res 19(4):556-66